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Title: A Multiwavelength Study of Flaring Activity in the High-energy Peaked BL Lac Object 1ES 1959+650 During 2015–2016

Abstract

We present the results from a multiwavelength study of the flaring activity in the high-energy peaked BL Lac object 1ES 1959+650 during 2015 January–2016 June. The source underwent two major outbursts, during 2015 March and 2015 October, across the whole electromagnetic spectrum (EMS). We used data from Fermi -LAT and Swift -XRT/UVOT, and optical data from Mt. Abu InfraRed Observatory and Steward Observatory to look for possible correlations between the emissions at different energies and the nature of the variability during the flaring state. During the 2015 October outburst, the nightly averaged V -band brightest magnitude, 14.45(0.03), and faintest magnitude, 14.45(0.03), were recorded. Apart from long-term flares, rapid and short-term variabilities were noticed at all energies. Our study suggests that the flaring activities at all frequencies, with diverse flare durations and time lags, are correlated. The magnetic field strength is estimated to be 4 G using the synchrotron-cooling timescale (2.3 hr), and the upper limits on the sizes of both emission regions, γ -ray and optical, are estimated to be of the order of 10{sup 16} cm. The quasi-simultaneous flux enhancements in 15 GHz and VHE γ -ray emissions indicate a fresh injection of plasma into the jet, which interactsmore » with a standing submillimeter core, resulting in co-spatial emissions across the EMS. The synchrotron peak shifts to higher frequency in the spectral energy distribution while the γ -ray spectra softens during the flaring. The shape of the inverse-Compton spectra indicates a change in the particle energy distribution pre- and post-flare.« less

Authors:
; ; ; ;  [1]
  1. Astronomy and Astrophysics Division, Physical Research Laboratory, Ahmedabad, Gujarat 380009 (India)
Publication Date:
OSTI Identifier:
22679721
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 846; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; BL LACERTAE OBJECTS; BLACK HOLES; CORRELATIONS; COSMIC GAMMA BURSTS; COSMIC GAMMA SOURCES; EMISSION; ENERGY SPECTRA; GALAXIES; GAMMA SPECTRA; GHZ RANGE; INJECTION; MAGNETIC FIELDS; QUASARS; STELLAR FLARES; SYNCHROTRON RADIATION

Citation Formats

Kaur, Navpreet, Chandra, S., Baliyan, Kiran S, Sameer, and Ganesh, S. A Multiwavelength Study of Flaring Activity in the High-energy Peaked BL Lac Object 1ES 1959+650 During 2015–2016. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA86B0.
Kaur, Navpreet, Chandra, S., Baliyan, Kiran S, Sameer, & Ganesh, S. A Multiwavelength Study of Flaring Activity in the High-energy Peaked BL Lac Object 1ES 1959+650 During 2015–2016. United States. doi:10.3847/1538-4357/AA86B0.
Kaur, Navpreet, Chandra, S., Baliyan, Kiran S, Sameer, and Ganesh, S. Sun . "A Multiwavelength Study of Flaring Activity in the High-energy Peaked BL Lac Object 1ES 1959+650 During 2015–2016". United States. doi:10.3847/1538-4357/AA86B0.
@article{osti_22679721,
title = {A Multiwavelength Study of Flaring Activity in the High-energy Peaked BL Lac Object 1ES 1959+650 During 2015–2016},
author = {Kaur, Navpreet and Chandra, S. and Baliyan, Kiran S and Sameer and Ganesh, S.},
abstractNote = {We present the results from a multiwavelength study of the flaring activity in the high-energy peaked BL Lac object 1ES 1959+650 during 2015 January–2016 June. The source underwent two major outbursts, during 2015 March and 2015 October, across the whole electromagnetic spectrum (EMS). We used data from Fermi -LAT and Swift -XRT/UVOT, and optical data from Mt. Abu InfraRed Observatory and Steward Observatory to look for possible correlations between the emissions at different energies and the nature of the variability during the flaring state. During the 2015 October outburst, the nightly averaged V -band brightest magnitude, 14.45(0.03), and faintest magnitude, 14.45(0.03), were recorded. Apart from long-term flares, rapid and short-term variabilities were noticed at all energies. Our study suggests that the flaring activities at all frequencies, with diverse flare durations and time lags, are correlated. The magnetic field strength is estimated to be 4 G using the synchrotron-cooling timescale (2.3 hr), and the upper limits on the sizes of both emission regions, γ -ray and optical, are estimated to be of the order of 10{sup 16} cm. The quasi-simultaneous flux enhancements in 15 GHz and VHE γ -ray emissions indicate a fresh injection of plasma into the jet, which interacts with a standing submillimeter core, resulting in co-spatial emissions across the EMS. The synchrotron peak shifts to higher frequency in the spectral energy distribution while the γ -ray spectra softens during the flaring. The shape of the inverse-Compton spectra indicates a change in the particle energy distribution pre- and post-flare.},
doi = {10.3847/1538-4357/AA86B0},
journal = {Astrophysical Journal},
number = 2,
volume = 846,
place = {United States},
year = {Sun Sep 10 00:00:00 EDT 2017},
month = {Sun Sep 10 00:00:00 EDT 2017}
}